1. Field of the Disclosure
The present disclosure generally relates to automated test equipment and more particularly to determining the integrity of wired communication links by testing for excessive signal loss at various frequencies.
2. Background Information
Numerous services are being offered over enhanced telephone networks, including broadband Internet access and high definition television services, as well as conventional telephone services. Telephony providers enable these services typically through use of digital subscriber line (DSL) technology, including High Speed DSL (HDSL), Very High Speed DSL (VDSL) and Asymmetric DSL (ADSL) services.
When a telephony provider branches into other markets, it is efficient to incorporate existing infrastructure to the extent possible when provisioning new services. For example, a VDSL provider that supports broadband Internet or high definition television services connects to a customer's location through conventional public switched telephone network (PSTN) infrastructure that supports VDSL, including central offices and twisted wire pairs extending to a customer location. Once on premises, though, the VDSL provider may elect to use coaxial cable previously deployed in the customer's home or office (e.g., to support cable television services) to distribute data and video signals to various receivers. However, the VDSL provider must assure that the existing infrastructure adequately supports the requirements of all aspects of the VDSL service, especially across the wire link from the network interface device (NID), which interfaces the customer network and the PSTN, to the customer premises equipment (e.g., a router or residential gateway) that interfaces with the various customer devices.
DSL signal loss currently is measured over wired links, such as coaxial cables, with DSL signals present on the line, indicating only an average loss over the entire frequency range and requiring the presence of DSL signals (e.g., from previously provisioned DSL services). Further, automated testers presently exist that enable technicians to determine electrical resistance across coaxial cables when there is signal from the transmit site present on the line, for example. However, testing resistance does not provide the information necessary to determine whether a wired link supports a frequency spectrum sufficient to enable proper functionality of a particular service, such as VDSL.